DE102012112705A1 - Process for producing methanol from carbon dioxide - Google Patents

Abstract

A process is proposed for the production of methanol from a feedstock rich in carbon dioxide, in which a carbon dioxide-rich feed stream is fed to a methanization stage where it is reacted with hydrogen to give a methane-rich stream. This is subsequently reacted together with a hydrocarbon-rich feed stream in a reforming stage to synthesis gas, which is then reacted to the final product methanol. Advantageously, an existing pre-reforming step is used as the methanation step.

Description

Field of the invention

The invention relates to a multi-stage process for the production of methanol by reacting a first, carbon dioxide-rich feed stream in addition to a second, hydrocarbon-rich feed stream, for example natural gas or naphtha. The invention further relates to a system for carrying out the method according to the invention.

State of the art

There is a growing demand for technologies that allow the greenhouse gas carbon dioxide (CO ₂ ) to be recycled and converted into climate-neutral end products. As one of these methods, the alternative methanol synthesis is investigated, in which - in contrast to the classical method - the synthesis gas used in addition to hydrogen (H ₂ ) contains no or only small amounts of carbon monoxide (CO), but predominantly or exclusively carbon dioxide. Fundamentals of classical, CO-based methanol synthesis can be found, for example, in Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 1998 Electronic Release, Chapter "Methanol", Subchapter 5.2 "Synthesis" ,

The synthesis of methanol from CO ₂ and H ₂ or CO ₂ -rich synthesis gas is basically possible and has already been investigated in earlier work, for example in the article of H. Göhna and P. König, "Producing methanol from CO2", Chemtech 24 (1994), pp. 36-39 , where "CO ₂ -rich synthesis gas" in this work synthesis gases are understood with CO ₂ concentrations of more than 8 vol .-%. However, it has the disadvantage over the classic methanol synthesis with CO-rich synthesis gas that the CO ₂ -based methanol synthesis proceeds more slowly. In the 1990s, therefore, Lurgi developed a process which provides an additional adiabatic reactor upstream of the synthesis loop (see above reference). Furthermore, significantly more water vapor is formed in the CO ₂ -based methanol synthesis, so that there is a higher potential for condensation. Condensation of water on the methanol synthesis catalyst can cause chemical modification and mechanical destruction of the catalyst. It can thus be seen that the methanol synthesis based purely on carbon dioxide is technically more complicated and therefore difficult to realize in already existing methanol plants.

Description of the invention

The object of the present invention is therefore to provide a process for preparing methanol by reacting carbon dioxide, which overcomes the difficulties described above and is easy to integrate into an existing plant for the synthesis of methanol by the classical method.

• (a) Zuführen des ersten, kohlendioxidreichen Einsatzstroms zu mindestens einer Methanisierungsstufe und Umsetzen des ersten Einsatzstroms mit Wasserstoff unter Methanisierungsbedingungen zu einem methanreichen Strom,
• (b) Zuführen des methanreichen Stroms zu mindestens einer Synthesegaserzeugungsstufe und gemeinsames Umsetzen mit dem zweiten, kohlenwasserstoffreichen Einsatzstrom zu einem Kohlenstoffoxide und Wasserstoff enthaltenden Synthesegasstrom unter Synthesegaserzeugungsbedingungen,
• (c) Zuführen des Synthesegasstroms zu einer in einen Synthesekreislauf eingebetteten Methanolsynthesestufe und Umsetzen zu einem Methanol umfassenden Produktstrom unter Methanolsynthesebedingungen,
• (d) Abtrennung des Methanols aus dem Methanol umfassenden Produktstrom und optional Reinigung des Methanols zu einem Methanolendproduktstrom,
• (e) Abtrennung eines Kohlenstoffoxide und Wasserstoff enthaltenden Spülstroms aus der Methanolsynthesestufe.

The above object is achieved with the invention according to claim 1 with a method for producing methanol from a carbon dioxide-rich stream as a first feed stream and a hydrocarbon-rich stream as a second feed stream, comprising the following process steps:

• (a) supplying the first, carbon dioxide-rich feed stream to at least one methanation stage and reacting the first feed stream with hydrogen under methanation conditions to a methane-rich stream,
• (b) supplying the methane-rich stream to at least one synthesis gas generating step and co-reacting with the second hydrocarbon-rich feed stream to produce a synthesis gas stream containing carbon oxides and hydrogen under synthesis gas generation conditions;
• (c) supplying the synthesis gas stream to a methanol synthesis step embedded in a synthesis loop and reacting to a methanol-comprising product stream under methanol synthesis conditions,
• (d) separating the methanol from the product stream comprising methanol and optionally purifying the methanol to a final methanol product stream,
• (e) separating a purge stream containing carbon oxides and hydrogen from the methanol synthesis stage.

The invention also relates to a system for carrying out the process according to the invention, which comprises at least one methanation reactor, at least one reforming reactor equipped with a heating device, at least one methanol synthesis reactor, at least one recycling line for recycling unreacted synthesis gas to the methanol synthesis reactor and a methanol separator.

Further advantageous embodiments of the method according to the invention can be found in the dependent claims 2 to 9, further advantageous embodiments of the inventive system in claims 11 to 14.

The invention is based on the recognition that the opposite of the classic Methanol synthesis new feed stream, the carbon dioxide-rich stream, not, as taught in the prior art, the methanol synthesis abandoned, but is already introduced in the synthesis gas production in the process. Optionally, additional hydrogen is also given up there. By means of an additional, structurally simple, adiabatic shaft reactor, the CO ₂ imported into the process is first converted into methane with hydrogen (methanation). The hydrogen required for this purpose, after any work-up from the process step according to claim 1 (e) originate or be obtained from an external source. Alternatively, the additional hydrogen addition may also be omitted if the process chain includes a pre-reforming step (pre-reforming). Since hydrogen is formed during the pre-reforming, the carbon dioxide-rich stream can be given off to the pre-reformer and converted there to methane. It is advantageous that the catalysts used for the pre-reforming often also have sufficient activity for the methanation of carbon dioxide. The methane formed from the two feed streams is subsequently converted to synthesis gas in a manner known per se, although reforming processes known from the prior art, such as steam reforming (steam reforming) or autothermal reforming (ATR), but also other processes for producing synthesis gas are used such as the gasification of petroleum fractions, coal or biomass. At first, it seems absurd to first form methane in the methanation stage and then convert it back to syngas. Surprisingly, however, it has been found that the process according to the invention has advantages over the processes described in the prior art, since the reaction can be implemented significantly more easily in terms of process engineering. The resulting heat can be used directly in gas production and does not have to be decoupled by heat exchangers. The CO ₂ methanation according to the reaction equation CO ₂ + 2H ₂ = CH ₄ + 2H ₂ O resulting product water has an advantageous effect in the production of synthesis gas since it suppresses the formation of soot or carbonization of the catalysts used there and, moreover, can be separated off in the precipitator which is already present and which is downstream of the reforming. In addition, it eliminates as ballast for the synthesis of methanol, so that the local apparatus and pipelines can be reduced in size with the same power.

As in the context of the process according to the invention carbon dioxide-rich stream each gas stream with increased carbon dioxide concentration, but also a CO ₂ -Reinstrom can be construed. It is therefore possible to use CO ₂ -rich or CO ₂ -riched offgas streams which may need to be subjected to a pretreatment to remove catalyst poisons, for example sulfur components. The CO ₂ content of such carbon dioxide rich streams is preferably more than 50% by volume, particularly preferably more than 90% by volume. Most preferably, carbon dioxide rich streams are processed with CO ₂ contents above 95% by volume, such as those obtained with the regeneration exhaust gas of a physisorptive CO ₂ capture process.

As a hydrocarbon-rich stream, the starting materials or feed mixtures can be used, which are also used in conventional synthesis gas production processes, ie in particular natural gas or vaporized naphtha as typical feedstocks for reforming. Likewise, however, hydrocarbon-rich streams may also be petroleum fractions, coal or biomass, which may be fed to the synthesis gas generation stage under specific conditions known per se to those skilled in the art.

The reaction conditions and catalysts suitable for carrying out the methanation of CO ₂ according to the above reaction equation are known to the person skilled in the art. They are for example in the international patent application WO 2010/006 386 A2 and discussed in the references mentioned there.

As the synthesis gas generation stage, the synthesis gas production processes known from the prior art, such as steam reforming or autothermal reforming (ATR), and specific gasification processes for non-volatile hydrocarbon-rich streams, for example heavy petroleum fractions, coal or biomass, can be used. Here too, suitable process conditions from the extensive state of the art are known to the person skilled in the art. The relevant prior art is used for example in Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 1998 Electronic Release, Chapter "Gas Production", Subchapter 2, "Catalytic Reforming of Natural Gas and Other Hydrocarbons" summarized.

A modern, two-stage process for the preparation of methanol, which can preferably also be used in carrying out the process according to the invention is, for example, from EP 0 790 226 B1 known. The methanol is produced in a cyclic process in which a mixture of fresh and partially reacted synthesis gas is first fed to a water-cooled reactor and then to a gas-cooled reactor, in which the synthesis gas is fed to one copper-based catalyst is converted to methanol. The methanol produced in the process is separated from the synthesis gas to be recycled after cooling below the dew point in a condenser. The remaining synthesis gas is then passed as a countercurrent refrigerant through the gas-cooled reactor and preheated to a temperature of 220 to 280 ° C before being introduced into the first synthesis reactor. A portion of the synthesis gas to be recycled is removed from the process as a purge stream to prevent inert components within the synthesis loop from accumulating. The European patent specification EP 0 790 226 B1 The skilled person can also refer to other conditions for carrying out the methanol synthesis.

Preferred embodiments of the invention

A preferred embodiment of the method according to the invention provides that the purge stream is fed to a gas separation stage and separated therein into a hydrogen-rich recycle stream and into a hydrogen-poor recycle stream. In this way, the valuable constituents of the synthesis gas separated off from the methanol synthesis cycle, in particular the hydrogen, can continue to be used.

It is particularly preferred in this case if the hydrogen-rich recycle stream is recycled to the at least one methanation stage and / or to the methanol synthesis stage. In this way, the valuable hydrogen can be used for methanation of the carbon dioxide introduced or for methanol synthesis.

It is furthermore advantageous if the hydrogen-poor recycle stream is returned to the at least one synthesis gas generation stage and used there as fuel. Since this still has a significant calorific value, it can be used advantageously for undercutting the reformer furnace of a reforming plant, for example a steam reforming plant.

An advantageous embodiment of the method according to the invention further provides that the at least one synthesis gas generation stage comprises a pre-reforming stage (Prereformer) and a Hauptreformierungsstufe, wherein the first, carbon dioxide-rich feed stream of the pre-reforming fed and at least partially converted to methane in this. A pre-reformer is generally used whenever the hydrocarbon-rich feedstock to be converted to synthesis gas is natural gas with a significant proportion of ethane or even higher hydrocarbons. In the pre-reformer, the higher hydrocarbons are partially or even completely converted to methane. Surprisingly, it is possible without disturbing the pre-reforming of the hydrocarbon-rich feed stream to give the Prereformer the carbon dioxide-rich feed stream and optionally hydrogen, wherein parallel to the Vorreformierungsreaktion proceeds the methanation of the carbon dioxide, so that this is converted to methane. It is often possible to dispense with hydrogen addition, since hydrogen is already formed in the pre-reforming of the hydrocarbon-rich feed stream. There are also energetic advantages, since the heat requirement of the Prereformers for the endothermic Vorreformierungsreaktion considerably reduced by the coupling with the exothermic CO ₂ methanation.

However, if additional hydrogen is required, it is provided in a further preferred embodiment that the hydrogen additionally charged to the pre-reforming stage originates at least partially from the gas separation stage. This reduces equipment costs because less or no expensive hydrogen has to be imported into the process.

It is also advantageous if the pre-reforming stage contains a catalyst which is active both for the pre-reforming and for the methanation. This results in logistical advantages in the procurement and handling of the required catalyst. It is particularly advantageous in this case that some of the active catalysts for the pre-reforming of higher hydrocarbons, nickel-containing catalysts also show sufficient activity for the methanation of carbon dioxide.

A particular embodiment of the system according to the invention provides that a hydrogen separation plant in the form of a pressure swing absorption system or a membrane separation plant for hydrogen separation from the purge stream is present. Both methods are known per se. In particular, the pressure swing adsorption is often used in the downstream of a steam reforming product workup.

It is particularly preferred if in the system according to the invention a return line for a hydrogen-rich recycle stream from the hydrogen separation plant to the methanization reactor and / or to the at least one methanol synthesis reactor is present. In this way, the valuable hydrogen can be used for methanation of the carbon dioxide introduced or for methanol synthesis.

A further advantageous embodiment of the system according to the invention is characterized by a return line for a low-hydrogen recycle stream from the hydrogen separation plant to the heating device of the reforming reactor. Since the hydrogen-poor recycle stream still has a significant calorific value, it can be used to advantage undercutting the reformer furnace of a steam reforming plant.

Particular advantages are obtained when the plant according to the invention comprises a pre-reforming reactor (pre-reformer) and a main reforming reactor, wherein the pre-reforming reactor is also used as a methanization reactor. A pre-reformer is generally used whenever the hydrocarbon-rich feedstock to be converted to synthesis gas is natural gas with a significant proportion of ethane or even higher hydrocarbons. In the pre-reformer, the higher hydrocarbons are partially or even completely converted to methane. Surprisingly, it is possible without disturbing the pre-reforming of the hydrocarbon-rich feed stream to give the Prereformer the carbon dioxide-rich feed stream and optionally hydrogen, wherein parallel to the Vorreformierungsreaktion proceeds the methanation of the carbon dioxide, so that this is converted to methane. It is often possible to dispense with hydrogen addition, since hydrogen is already formed in the pre-reforming of the hydrocarbon-rich feed stream. There are also energetic advantages, since the heat requirement of the Prereformers for the endothermic Vorreformierungsreaktion considerably reduced by the coupling with the exothermic CO ₂ methanation.

embodiments

Further developments, advantages and applications of the invention will become apparent from the following description of exemplary embodiments and the drawings. All described and / or illustrated features alone or in any combination form the invention, regardless of their combination in the claims or their dependency.

Show it

1 a method of prior art methanol synthesis as a first comparative example,

2 a method for methanol synthesis according to the prior art as a second comparative example,

3 the method according to the invention according to a first embodiment,

4 the inventive method according to a second embodiment.

In the in 1 shown block flow diagram of a process for methanol synthesis according to the prior art, the feedstock or the feedstock mixture, such as natural gas or naphtha, via line 10 in the process and becomes the synthesis gas generation stage 11 directed. This is usually designed as a steam reformer or as an autothermic reformer; Also possible are combinations of the aforementioned types of reformer or entirely different synthesis gas production processes, such as non-catalytic partial oxidation, gasification of heavy petroleum fractions or refinery solids, coal gasification, gasification of biomass, either alone or in combination with the aforementioned reformer types and / or synthesis gas production processes. Suitable operating conditions for these process steps are known to the person skilled in the art.

The feed mixture converted to crude synthesis gas leaves via line 12 the synthesis gas generating stage and is - optionally after further, in 1 Not shown conditioning - the methanol synthesis stage 13 fed. In principle, all known processes for methanol synthesis can be used here, it being possible to use both single-stage and multistage processes; the nature of the procedure is therefore in 1 not detailed. The suitable conditions for the operation of the methanol synthesis are known in the art. The final product methanol is via line 14 discharged from the process. Further, a purge or purge gas stream via line 15 removed from the methanol synthesis stage, which contains both in the sense of methanol synthesis inert components such as methane, nitrogen or noble gases, but also unreacted syngas components such as carbon oxides or hydrogen. The purge gas becomes a gas separation stage 16 fed, which can be configured according to methods known per se, for example by the pressure swing adsorption (PSA) or by a membrane separation process. In the gas separation stage, a hydrogen-enriched stream is obtained via the lines 17 and 12 is recycled to the methanol synthesis stage. A hydrogen-depleted gas stream is passed over line 18 as fuel gas to the synthesis gas generation stage 11 recycled.

In 2 schematically a modified process for methanol synthesis is indicated as a block flow diagram, which is optimized for the processing of CO ₂ -rich synthesis gas. As described above, such methods have already been described in the prior art. It will be here In particular, reference is made to the work of Göhna and König, which the skilled artisan can find suitable conditions for operating such a modified method for methanol synthesis. Via wire 12 a feedstream containing carbon dioxide and hydrogen enters the modified methanol synthesis stage 13A which is optimized for the processing of CO ₂ -rich synthesis gas compared to prior art methanol synthesis methods. Via wire 14 the final product methanol is discharged from the process. Further details of the process, such as synthesis gas production or the work-up of the purge gas removed from the methanol synthesis, are described in US Pat 2 not shown.

In 3 a method for methanol synthesis according to a first embodiment of the invention is shown as a block flow diagram. Again, natural gas or naphtha passes as a feed mixture over line 10 in the process and becomes the synthesis gas generation stage 11 passed, which is designed as a reforming stage. In the reforming step, steam reforming or autothermal reforming or a combination of both methods can be used. Also possible are combinations of the aforementioned types of reformer or entirely different synthesis gas production processes, such as non-catalytic partial oxidation, gasification of heavy petroleum fractions or refinery solids, coal gasification, gasification of biomass, either alone or in combination with the aforementioned reformer types and / or synthesis gas production processes , Suitable operating conditions for the mentioned process stages are known to the person skilled in the art.

Via wire 19 becomes a methanation stage 20 fed a CO ₂ -rich gas stream to which optionally hydrogen can be added. The addition of hydrogen is optional, as well as process-own hydrogen, by means of gas separation stage 16 from the methanol synthesis 13 via wire 15 discharged purge gas is recovered, via line 17A to the methanation stage 20 is returned. The addition of hydrogen to the CO ₂ -rich gas stream is therefore only required if the via line 17A recycled hydrogen can not meet the stoichiometric demand in the methanation or a return is not possible because no own process hydrogen is available, for example, when commissioning the process. With regard to the selection of suitable methanation process conditions, those skilled in the art may refer to the literature and make any necessary adjustments based on their skill in the art. Suitable process conditions are described for example in the international patent application WO 2010/006 386 A2 and discussed in the references mentioned there.

The CO ₂ -rich gas stream is in the methanation stage 20 converted into a methane-rich product stream, which via line 21 supplied to the synthesis gas generation stage or reforming stage and in this together with the via line 10 supplied natural gas or naphtha is converted to raw synthesis gas.

The feed mixture converted to crude synthesis gas leaves via line 12 the synthesis gas generation stage or reforming stage and is - optionally after further, in 3 Not shown conditioning - the methanol synthesis stage 13 fed. In the present embodiment, a two-stage process for methanol synthesis with water and gas-cooled synthesis reactors is particularly preferred, as described in the document EP 0 790 226 B1 is described. In principle, however, also usable in the process according to the invention is the synthesis of methanol by a one-step process. Details of this procedure will be available in 3 not shown. However, since this is a process for the processing of conventional, non-CO ₂ -rich synthesis gases, here again all known from the prior art, one- or multi-stage process for methanol synthesis can be used.

The final product methanol is via line 14 discharged from the process. Further, a purge or purge gas stream via line 15 removed from the methanol synthesis stage, which contains both in the sense of methanol synthesis inert components such as methane, nitrogen or noble gases, but also unreacted syngas components such as carbon oxides or hydrogen. The purge gas becomes a gas separation stage 16 fed, which is designed as pressure swing adsorption (PSA). However, it is also possible to use other separation processes, for example membrane separation processes. In the gas separation stage, a hydrogen-enriched gas stream is obtained via the lines 17 and 12 is recycled to the methanol synthesis stage. Further, via line 17A a substream of the hydrogen-enriched gas stream to the methanation stage 20 recycled.

As with the in 1 The process shown is a hydrogen-depleted gas stream via line 18 as fuel gas to the synthesis gas generation stage 11 recycled.

4 shows a further process for methanol synthesis according to a second embodiment of the invention as a block flow diagram. This is largely analogous to that in 3 illustrated embodiment. Therefore, those related to the description of 3 disclosed features for the inventive method after 4 , However, in the in 4 illustrated embodiment, the natural gas or naphtha comprehensive feed mixture initially a modified methanation 20A fed simultaneously as Vorreformer (Prereformer) and thus causes a degradation of higher hydrocarbons to methane. It is advantageous that the catalysts used for the pre-reforming, for example, nickel-based, often also have sufficient activity for the methanation of carbon dioxide. There are therefore obtained special advantages, since two process steps can be carried out in a single, structurally simple reactor. If appropriate, the catalyst volume should be adjusted accordingly with regard to the desired conversions of the higher hydrocarbons and of the carbon dioxide to methane.

Industrial Applicability

The invention proposes a process for the production of methanol from carbon dioxide-rich feed streams, in which these are reacted together with the classical feedstocks for the methanol synthesis to give the end product methanol. In this respect, the inventive method is a contribution to the material use of the greenhouse gas carbon dioxide, wherein at the same time derived from fossil raw materials, such as natural gas or naphtha, are partially saved.

LIST OF REFERENCE NUMBERS

10

management

11

Synthesis gas generation stage

12

management

13

Methanol synthesis stage

13A

modified methanol synthesis step

14

management

15

management

16

Gas separation stage

17

management

17A

management

18

management

19

management

20

methanation

20A

modified methanation stage, pre-reformer

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2010/006386 A2 [0011, 0034]
• EP 0790226 B1 [0013, 0013, 0036]

Cited non-patent literature

• Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 1998 Electronic Release, Chapter "Methanol", Subchapter 5.2 "Synthesis" [0002]
• H. Göhna and P. König, "Producing methanol from CO2", Chemtech 24 (1994), pp. 36-39 [0003]
• Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 1998 Electronic Release, Chapter "Gas Production", Subchapter 2, "Catalytic Reforming of Natural Gas and Other Hydrocarbons" [0012]

Claims (14)

A process for producing methanol from a carbon dioxide-rich stream as a first feed stream and a hydrocarbon-rich stream as a second feed stream, comprising the following process steps: (a) supplying the first, carbon dioxide-rich feed stream to at least one methanation stage and reacting the first feed stream with hydrogen under methanation conditions to a methane-rich stream, (b) supplying the methane-rich stream to at least one synthesis gas generating step and co-reacting with the second hydrocarbon-rich feed stream to produce a synthesis gas stream containing carbon oxides and hydrogen under synthesis gas generation conditions; (c) supplying the synthesis gas stream to a methanol synthesis step embedded in a synthesis loop and reacting to a methanol-comprising product stream under methanol synthesis conditions, (d) separating the methanol from the product stream comprising methanol and optionally purifying the methanol to a final methanol product stream, (e) separating a purge stream containing carbon oxides and hydrogen from the methanol synthesis unit. A method according to claim 1, characterized in that the purge stream is fed to a gas separation stage and is separated in this in a hydrogen-rich recycle stream and in a hydrogen-poor recycle stream. A method according to claim 2, characterized in that the hydrogen-rich recycle stream is recycled to the at least one methanation and / or to the methanol synthesis stage. A method according to claim 2, characterized in that the low-hydrogen recycle stream is returned to the at least one synthesis gas generating stage and used there as fuel. The method of claim 2 to 4, characterized in that the at least one synthesis gas generating stage comprises a Vorreformierungsstufe (Prereformer) and a Hauptreformierungsstufe, wherein the first, carbon dioxide-rich feed stream of the pre-reforming fed and at least partially converted to methane in this. A method according to claim 5, characterized in that the Vorreformierungsstufe additional hydrogen is given up. Process according to Claim 6, characterized in that the hydrogen additionally charged to the pre-reforming stage originates at least partly from the gas separation stage. A method according to claims 5-7, characterized in that the pre-reforming step contains a catalyst which is active for both the pre-reforming and the methanation. A method according to claim 8, characterized in that the catalyst of the pre-reforming stage contains nickel. Plant for carrying out a process according to one of claims 1 to 9, comprising at least one methanization reactor, at least one reforming reactor equipped with a heating device, at least one methanol synthesis reactor, at least one recycle line for recycling unreacted synthesis gas to the methanol synthesis reactor and a methanol separator. Plant according to claim 10, characterized by a hydrogen separation plant in the form of a pressure swing adsorption plant or a membrane separation plant for hydrogen separation from the purge stream. Plant according to claim 11, characterized by a recirculation line for a hydrogen-rich recycle stream from the hydrogen separation plant to the methanization reactor and / or to the at least one methanol synthesis reactor. Installation according to claim 11, characterized by a return line for a low-hydrogen recycle stream from the hydrogen separation plant to the heating device of the reforming reactor. Plant according to claim 10 to 12, characterized by a pre-reforming reactor and a main reforming reactor, wherein the pre-reforming reactor is also used as a methanization reactor.

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